One type of well has part of a rotary pump, such as a progressive cavity pump stator, secured to a lower end of a string of tubing. The tubing is located within casing, and the upper end of the tubing is supported in a wellhead at the surface. A motor assembly located at the surface is coupled to a string of rods that lead through the tubing. A rotor on the lower end of the rods fits within the pump stator. The motor assembly rotates the rods and the rotor to cause the pump to deliver well fluid up the tubing to the surface. These wells are usually shallow, and the well fluid is typically viscous oil.
In some wells, debris such as sand flows from the earth formation into the pump. The sand tends to settle and accumulate in the tubing above the pump. This accumulation restricts the passage of well fluid to the surface.
Various techniques are used to reduce sand flowing from the formation, but often some sand will still accumulate in the tubing. Also, a sand cleaning procedure utilizing coiled tubing is known. In this procedure, the operator disconnects the motor assembly, which is usually a top drive mounted on top of the wellhead assembly. The operator then uses a coiled tubing injector to push coiled tubing down the tubing alongside the rods. The coiled tubing is a continuous steel pipe that winds onto a large portable reel. The operator pushes the open lower end of the coiled tubing into the sand accumulation and pumps water down the coiled tubing. The water flows back up the coiled tubing, along with sand. While this technique is workable, pulling the top drive motor assembly is time consuming.